Dressed in knee-high black rubber boots, a brimmed hat, and loose-fitting pants and shirt, Tama Matsuoka Wong saunters into a field near the parking lot at Tower Hill Botanic Garden in Boylston. It’s Saturday morning, the day before Father’s Day, and Matsuoka Wong, who will be teaching a class on foraging, has arrived an hour early to survey the field.

She and Eddy Leroux, the chef de cuisine at Daniel, a three-star Michelin restaurant in New York, are the authors of a popular field guide and cookbook, “Foraged Flavor,” published in 2012 by Clarkson Potter.

Everyone comes casually dressed, some wearing boots and carrying hats. Many have books to be signed and stories they hope to share, briefly, warmly, during the book signing after the class.

There is a mother and son from Concord, Bob and Mary Krueger, who sit in the front row so Mary, 99, is able to hear and see. There is the Gauthier family from Sterling: Anne, Dave, and their 12-year-old twin girls, Nadia and Tanya, celebrating Father’s Day, a surprise revealed so late in the morning that Dave had to be assured that his worn jeans with frayed knees were perfect attire for their destination. And Cathy Button, a high tech professional from Concord; Carol and Carl Canner, Groton
artists on their way to a wedding in the Berkshires; and Jennifer Scott, a writer from Milford, with her
9-year-old son, Joey.

“This isn’t about being a ‘survivor man,’ eating twigs off a tree,” Matsuoka Wong tells her audience. “Foraging is how we evolved, how we ate before we had agriculture. In the rest of the world, they didn’t stop foraging even after the start of farming.”

Her interest in foraging took root the way weeds do, a convergence of chance and opportunity.

“I didn’t start out being interested in this wild food craze,” she says. “I wanted to know about the plants around my yard.”

But a trip to Daniel with friends in 2009 turned a budding interest into a passion: at the urging of the friends who had invited Matsuoka Wong and her husband to dinner, she took some of her backyard weeds to Leroux, and asked the chef to use them as ingredients for the dinner he would prepare for the group. Afterward, he would tell her: “Mrs. Wong, I like your weeds. Bring me everything!”

The author said she refused the chef’s offer to pay her, telling him, “No, I just want recipes. The information is what is valuable.”

Since then, Matsuoka Wong has been gathering the common edible weeds in her yard and meadow and delivering them to the restaurant. In the days when she was still working full time as a lawyer, she often dragged her large black plastic trash bag full of weeds onto the train and even across the trading floor. At least once at the train station, police officers pulled her aside to search and sniff her trash bag before sending her on her way.

She was in Massachusetts to conduct her class at Tower Hill, after which she was headed to Boston to sign books and then on to Woods Hole for another project. During her talk at Tower Hill, Matsuoka Wong suggests that the roughly 4,000 to 7,000 known edible weeds growing on uncultivated land around the world could be a source of food.

‘I didn’t start out being interested in this wild food craze. I wanted to know about the plants around my yard.’

“I started a vegetable garden on raised beds and found out it was on clay flood plain,” she says. “It lay desolate for much of the year.”

Meanwhile, green things were growing — things like chickweed and dandelions, purslane, lambs -quarters, yellow wood sorrel, and daylily — but they were plants that Matsuoka Wong was anxious to get rid of until she spoke with a guest from Japan about Japanese knotweed, considered by many to be the most noxious weed in the world.

“He said, ‘We eat knotweed in Japan. It’s a delicacy called itadori.’

“I was trying to get the weeds out, and I found an edible plants book that talked about using them for tea, salad, boiling them, and I knew that wouldn’t pass with the Wong family,” she says.

Edible weeds could become part of her family’s diet only if they were delicious.

At Tower Hill, she talks to her audience about regaining the connection between land and food that has sustained human beings from the beginning of time. Farmers talk proudly of rotating several crops to improve the soil, she says, but on a healthy prairie, an ecologist will point out that one square meter will sustain 50 varieties of plants.

“I don’t think we can top Mother Nature,” she says.

In the wild weed kingdom, she continues, there’s plenty for everyone: 21,000 plants growing wild in North America and 300,000 worldwide; between 4,000 and 7,000 known to be edible.

Compare that with the 25 to 60 vegetables, fruits, and grains cultivated or imported in industrialized nations. Add the enormous volume of water, an estimated 10,000 gallons a year used to water our lawns. And from a forager’s point of view, Matsuoka Wong says, we’re missing a green opportunity.

Still, there’s a learning curve. Start slowly, she says.

Identify one or two common edible weeds and use them. Try making a tempura with dandelion flowers or cook the early, light green leaves, which by now have matured and are bitter; sample yellow wood sorrel, the tiny, heart-shaped leaves sometimes known as “sour grass” and distinguished from the rounded leaves of clover, sprinkled into a salad, lavished on top of smoked salmon or placed inside a cheese sandwich.

Don’t cook yellow wood sorrel because it is too delicate and should be enjoyed raw.

Look for mugwort, chickweed, purslane, and lambsquarters. Experiment with the orange daylily and wild amaranth.

But first learn your plants, one at a time, and always be sure of what you have, where it comes from, and when it is in peak season and ready to eat.

Most green plants aren’t toxic, Matsuoka Wong says. But some will make you sick, and there are a few, such as poison hemlock, that, if you eat them, “You will die!” Learn the difference between toxic and poisonous. Keep in mind that 95 percent of all mushrooms are not edible.

It is also important to be aware of sustainability. You should know the difference between native and nonnative plants. Native plants have evolved with the landscape and are part of the web of life that connects plant, insect, and animals. Disturbing one affects the others. Picking too many, particularly by yanking out the roots, could eradicate the plant.

By contrast, digging up nonnative plants such as Japanese knotweed won’t disturb the landscape, so take as many as you can carry. Picked at peak season they will enhance recipes and nutrition, and even keep you full longer because of their nutrient density, she says.

On the grounds at Tower Hill, with a view of Mount Wachusett hidden behind a gauzy morning sky, Matsuoka Wong walks briskly and talks fast, a tie on her hat bobbing up and down. Suddenly, she stops.

“Pine tips!” she gushes, recounting how trendy Norwegian chefs are making use of the greens in places where the growing season is short. Then she looks up, spotting a gray bird about the size of a woman’s fist balancing on a pine bough.

“Oh look, a little bird,” she exclaims before reaching out to snip a bit of lime-green pine.

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